UV/EB radiation curing paint and ink are fast in curing, environment friendly, energy saving, and can be used on all kinds of base material, and therefore have wider and wider application in quite a few areas. With the development of UV/EB radiation curing paint and ink, there is higher and higher standard for the additives applied within. The traditional organic modified polysiloxane can no longer satisfy the needs of radiation curing systems and is gradually replaced by UV/EB curable acryloyl oxygen alkyl modified polysiloxane. Since UV/EB curable acryloyl oxygen alkyl modified polysiloxane has taken part in the film formation reaction, the smoothness of the coating layer can be maintained for a long time and the precipitation can be controlled to the lowest level.
Acryloyl oxygen alkyl modified polysiloxane can be obtained by different polycondensation or addition reaction. For example, the US patent document, U.S. Pat. No. 4,035,355, disclosed a method to prepare acryloyl oxygen alkyl modified polysiloxane, in which methyl chlorosilane and acryloyl group containing chlorosilane undergo hydrolytic condensation reaction. However, the hydrochloric acid released in the process has to be neutralized, which complicates the whole production procedure. Goldschmidt uses chlorinated polysiloxane to react with hydroxylated acrylic or trimethylolpropane acrylate or pentaerythritol triacrylate and undergo condensation reaction and obtain acryloyl oxygen alkyl modified polysiloxane. Tertiary amine is used to neutralize the byproduct, hydrochloric acid. Apart from precipitation which needs to be removed by filtration, the obtained products contain a large amount of Si—O—C bonds, which are unstable and easy to be hydrolyzed. U.S. Pat. No. 4,978,726, U.S. Pat. No. 6,548,568, CN101089031 disclosed a preparation method, in which hydrogen containing polysiloxane is reacted with unsaturated monomer (such as allyl glycidyl ether) and undergo hydrogen silicide addition, and (methyl) acrylic acid is used to open the epoxy ring to obtain acryloyl oxygen alkyl modified polysiloxane. The energy consumption of the esterification reaction in the last step is very high, and the double bond in (methyl) acrylic acid can self-polymerize in the last esterification and dehydration step. U.S. Pat. No. 5,977,282 disclosed a method, in which hydrogen containing siloxane is reacted with allyl polyether mono alcohol and undergo addition reaction and then react with crylic acid and undergo dehydration and condensation reaction to produce acryloyl oxygen alkyl modified polysiloxane. It still cannot be avoided the addition reaction between allyl polyether and the Si—H bonds of the hydrogen containing siloxane.
There are some other documents in which hydroxyl containing polysiloxane is reacted with (methyl) crylic acid and directly dehydrate to produce acryloyl oxygen alkyl modified polysiloxane. However, there still exists the danger of self-polymerization of the double bond of (methyl) crylic acid.